Effect of niobium and titanium on dynamic recrystallization behavior of low carbon steels

Using a Gleeble 3800 thermo-mechanical simulator, the effect of niobium and titanium on the dynamic re-crystallization (DRX) behavior of low carbon steels was investigated. Isothermal single compression tests were performed in the temperature range of 850 to 1 150 degrees C at constant. strain rates of 0.1 to 5 s(-1). The experimental results showed that the addition of niobium and titanium to the low carbon steels significantly increased both the peak stress and steady state stress. The activation energy of deformation Q(d) was larger than the activation energy associated with the steady state stress Q(ss). Furthermore, the difference between Q(d) and Q(ss) became significant because of the addition of niobium and titanium. DRX is effectively retarded because of solute dragging and dynamic precipitate pinning of niobium and titanium, resulting in higher values of the peak strain and steady state strain. Finally, the influence of niobium and titanium on the DRX kinetics and steady state grain size was determined.